Self-locking grate for deck drain fitting

ABSTRACT

A self-locking grate for a drain fitting body includes a plate having strainer holes and arcuate elongated openings near the periphery of the grate. Enlarged diameter portions of the elongated openings fit over studs connected to a drain, and the grate can be rotated to engage the studs, so that the grate is wedged to the drain fitting body without the use of screws. An inclined ledge, formed in the elongated openings, acts as a cam surface to wedge against the grate as it is rotated into the locked position. Despite the absence of screws, the grate is unlikely to loosen due to vibration or shock. A tool capable of simultaneously engaging distinct holes in the grate can be used to rotate the grate between the locked and unlocked positions. The invention also includes a kit for converting a conventional drain fitting and grate into a drain fitting and grate of the present invention.

BACKGROUND OF THE INVENTION

The present invention relates to floor drain and deck drain fittings, especially deck drain fittings used in marine applications, including ships, boats, barges, and other vehicles and structures such as drilling platforms. The invention provides a method and apparatus for easily removing and replacing a grate for a drain fitting, for the purposes of inspecting a drain body, clearing an obstruction, and/or cleaning and repairing any of the parts thereof.

It is known to provide drain pipes on ships, for removing water that may accumulate on a deck or platform. Such drain pipes typically terminate in a flared, generally conical structure, or drain fitting, which is capped with a grate. The grate prevents relatively large pieces of debris from falling into the drain fitting and causing clogs, while allowing water, and solid material having a relatively small size, to flow into the drain. The grate and drain structures are usually arranged so that the grate is essentially flush with the deck or platform. Thus, the drain pipe itself is typically located below the deck or platform, and the flared terminus of the drain is attached, typically by welding, to the surface of the deck or platform.

In the deck drains of the prior art, the grate is usually attached to the flared terminus by screws, which engage threads formed in studs or bosses attached to the inner body of the drain. Because drains need periodic cleaning and maintenance, these screws must be frequently removed, so that the grate can be lifted from the drain. When the maintenance operation is complete, the grate must be reinstalled by reinstalling the screws and tightening them.

The above design has several disadvantages, especially when maintaining the drain fitting while the marine vehicle is in a seaway. First, it is inconvenient to handle multiple screws while removing and reattaching the grate. One or more screws can easily become lost by rolling away, or they can even fall into the drain.

Secondly, a more serious problem arises when the grate has been removed and reattached many times. After many iterations, the drain fitting body threads for the screws are likely to become worn, and they eventually may become stripped. When the threads are stripped, repair is often a major undertaking, as it is often done by replacing the entire drain fitting. For drains that are welded to a metal deck or platform, the only way to replace them is to cut away portions of the surrounding deck. This is an operation that usually cannot be either conveniently or safely performed while at sea. To repair the drain adequately, it may be necessary to wait until the marine vehicle is in port.

If the subject deck or platform is also the surface of a tank, the replacement of a deck drain fitting is especially costly. This is because a fuel tank will require cleaning and degassing, with certification, before hot metal work is permitted.

The present invention provides a self-locking grate which does not require the use of screws, and which therefore avoids the problems described above. The grate of the present invention fulfills all of the purposes of grates of the prior art, while greatly simplifying the process for removal and replacement of the grate.

SUMMARY OF THE INVENTION

The present invention, in one aspect, comprises a self-locking grate for a drain fitting, the grate eliminating the need for screws for attaching the grate to the drain fitting.

The grate of the invention comprises a plate having a plurality of strainer holes, and a plurality of arcuate elongated openings. The elongated openings are arranged in a circular arc near the periphery of the plate. Each elongated opening includes an enlarged diameter portion, as well as an inclined ledge having a depth which varies along the length of the elongated opening.

The drain body includes a plurality of studs, of similar number and arrangement as the screws securing the strainer plates of the prior art. Each stud is sized to fit within the enlarged diameter portions of the openings, but has a head which is large enough to be caught within the elongated opening when the stud is not aligned with the enlarged diameter portion. The drain fitting also typically includes a flange for supporting the grate, so that the grate can rest conveniently over the drain, and be positioned such that the top surface of the grate is flush with the deck or platform surface.

The grate is locked onto the drain fitting by simply placing the grate on the drain fitting such that the studs pass through the enlarged diameter portions, and rotating the grate so that the studs become positioned near the opposite ends of the elongated openings, relative to the enlarged diameter portions. As the grate is so rotated, the inclined ledge acts as a cam surface, pressing upon the grate, so that when the grate has been rotated to the fullest extent permitted by the elongated openings, the grate becomes firmly wedged between the underside of the stud head and the ledge.

The grate can be rotated with the use of a tool which includes a pair of spaced-apart prongs, the prongs being sized to fit simultaneously within a pair of holes or openings in the grate. In a preferred embodiment, one prong of the tool may be pivoted relative to another prong, so that the positions of the prongs can be adjusted to insure that the prongs fit simultaneously into holes and/or openings in the grate. That is, the tool may take the form of an adjustable spanner wrench. When the prongs are engaged in this manner, the application of force to the tool produces the necessary torque to rotate the grate in the desired direction.

The invention also includes a kit for converting a drain fitting body and grate of the prior art into a drain fitting body and grate of the present invention. The kit includes a grate constructed according to the present invention, a plurality of threaded inserts to define threaded receptacles for the studs, and a plurality of screws which, when screwed into the inserts, comprise the studs which engage the grate. The kit may also include taps for threading holes to accommodate the inserts, and a tool for installing the inserts. The kit may also include a spanner wrench, or its equivalent, for use in locking and unlocking the grate from the drain.

The invention therefore has the primary object of providing a self-locking grate for a drain, the grate being especially useful in marine environments and in other applications.

The invention has the further object of providing a grate which can be attached to, and removed from, a drain fitting without the use of screws.

The invention has the further object of reducing the cost of maintenance of drains, by eliminating the need for screws in attaching a grate to a drain fitting.

The invention has the further object of simplifying the procedure for attaching and removing a grate from a drain, which is especially valuable when the marine vehicle is moving in a seaway.

The invention has the further object of reducing the cost of maintaining deck and platform drain systems, especially on a marine vessel.

The invention has the further object of providing a method for attachment and removal of a grate from a drain or equivalent component.

The invention has the further object of providing a kit for converting a drain fitting of the prior art into one made according to the present invention.

The reader skilled in the art will recognize other objects and advantages of the invention, from a reading of the following brief description of the drawings, the detailed description of the invention, and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 provides an exploded perspective view of the grate and drain fitting of the present invention, showing the grate separately from the drain fitting.

FIG. 2 provides a fragmentary perspective view of the grate and drain fitting of the present invention, showing the grate and drain fitting installed on a deck of a vessel, and showing the grate in an unlocked position.

FIG. 3 provides a fragmentary perspective view similar to that of FIG. 2, but wherein the grate has been rotated into the locked position.

FIG. 4 provides a plan view of a fragment of the grate of the present invention, showing the shape of the opening that receives studs positioned on the drain fitting.

FIG. 5 provides a cross-sectional view of the opening, taken along the line 5-5 of FIG. 4.

FIG. 6 provides a fragmentary top view of a portion of the grate of the present invention, showing its engagement with a stud, in an unlocked position.

FIG. 7 provides a view similar to that of FIG. 6, but showing the engagement of the stud in the locked position.

FIG. 8 provides a perspective view of the self-locking grate of the present invention, and also showing a tool for locking and unlocking the grate.

FIG. 9 provides a perspective view of the elements of a kit which can be used to convert drain fittings of the prior art into a drain fitting and grate of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention comprises a self-locking grate for a drain fitting. The basic structure of the invention is shown in the exploded perspective view of FIG. 1. Grate 1 comprises a cover for drain fitting body 2, the grate being placed over the drain fitting body as indicated by arrow 3. The drain fitting body includes a flared, generally conical terminus 4, which connects to a drain pipe 5. The drain fitting body includes a plurality of studs 6, the studs being permanently mounted to the interior of the flared terminus 4, as shown. A flange 7 provides a seat for the grate. Each stud defines a stud head, as shown.

The grate includes a plurality of strainer holes, such as those designated by reference numeral 8, the strainer holes comprising means for preventing relatively large debris from falling into the drain. The grate also includes arcuate elongated openings 9, each elongated opening having a portion that is of enlarged diameter relative to that of the remainder of the opening, to allow passage of, and engagement with, the stud heads. In the embodiment shown, there are four such elongated openings. The elongated openings are distinct from the holes. The elongated openings are arranged along a generally circular arc, near the periphery of the grate.

FIG. 2 shows the drain fitting body installed in, and flush with, deck 10, which may be the deck or platform of a marine vessel or other structure. In FIG. 2, the grate has been installed in the drain fitting, maintaining the relative rotational position of the grate shown in FIG. 1. That is, in FIG. 1, the positions of the enlarged diameter portions of the openings coincide with the positions of the studs, and when the grate is set down over the drain, as shown in FIG. 2, the studs easily pass through the openings. FIG. 2 represents an unlocked position, because in the position shown, the grate could simply be lifted away from the drain.

To lock the grate, one rotates the grate as indicated by arrow 11 of FIG. 2. FIG. 3 shows the grate in the locked position. In this position, the undersides of the stud heads engage inclined ledges 25 of the elongated openings (described below with respect to FIGS. 4 and 5) at positions where the diameter of the opening is smaller than that of the stud, so that the grate becomes wedged in position.

FIGS. 4 and 5 provide more details of the elongated openings 9. In particular, FIG. 4 clearly shows the portion 20 having an enlarged diameter, and the portion 21 having a reduced diameter. The cross-sectional view of FIG. 5 shows that the elongated opening includes an inclined ledge 25, which extends slightly upward as viewed from left to right in the figure. That is, the ledge has a depth which varies along the opening. Ledge 25 thus operates as a cam surface, applying pressure to the grate as the grate is rotated into the locked position. As the grate is rotated into the locked position, the grate becomes increasingly wedged between the ledge and the head of the stud. When the grate has been rotated to the fullest extent permitted by the elongated openings 9, the grate is not only prevented from being dislodged, vertically, from the drain fitting, but it is also firmly held in place by this wedging effect. Thus, the grate is unlikely to rotate spontaneously towards the unlocked position as a result of mechanical shock or vibration.

FIGS. 6 and 7 show the positions of one of the studs in the fully unlocked and locked states, respectively. In FIG. 6, the grate has been placed over the drain fitting body, but has not yet been locked. FIG. 7 shows the position of the stud when the grate has been rotated into the locked position. To unlock the grate, one simply rotates the grate in the direction of the arrow shown in FIG. 7.

FIG. 8 shows a tool 30 that can be used to lock and unlock the grate. The tool shown in the figure comprises a handle portion 31 which branches into prongs 32 and 33. Pins 34 and 35 are affixed to the ends of the prongs, and these pins fit within virtually any of the holes formed in the grate, including the strainer holes and the elongated openings. Prong 32 is connected to the handle portion through pivot pin 37, which allows the angle of the prong 32, relative to the handle, to be varied. Thus, the tool can be adjusted to fit simultaneously in two of the strainer holes and/or elongated openings. When the pins are inserted into the holes and/or openings, the tool can be rotated in either direction, as indicated by arrow 36, to lock or unlock the grate. Because the tool is engaged with the grate at two positions, the tool converts the force exerted by a user into the torque required to rotate the grate.

The invention is not limited to use with the tool that is shown and described. Many other equivalent tools could be used instead, and the present invention is intended to cover such variations. Such a tool should be capable of simultaneously engaging the grate at two different locations, so as to produce the desired torque. It may also be possible to lock or unlock the grate manually.

The invention also includes a kit for converting a drain fitting body and grate of the prior art into a drain fitting body and grate of the present invention. An example of such a kit is shown in FIG. 9.

The kit of FIG. 9 includes a strainer plate or grate, constructed according to the present invention as described above. A plurality of threaded inserts are provided, to be installed in the locations of the former screw holes of the prior art drain fitting. The threaded inserts are internally and externally threaded, so that after the inserts have been tightly screwed into their bores, the socket head screws shown in the figure can then be screwed into the inserts. The socket head screws, when installed, comprise the studs of the present invention, discussed above. The threaded inserts and the head screws therefore comprise means for providing studs in the drain fitting.

The kit may also include a tool for installing the threaded insert. In the embodiment shown, the tool includes lugs which enable the tool to engage a groove formed on the threaded insert, such that rotation of the tool causes the threaded insert to be screwed into its bore.

The kit may also include drill-taps for drilling out the screws in the prior art fitting, and for creating the threads in such bores that will engage the threaded inserts. The kit may also include a spanner wrench, or equivalent, for rotating the grate or strainer plate between the locked and unlocked positions.

While the assembly of components shown in FIG. 9 is preferred, the exact contents of the kit can vary. At a minimum, the kit should include the grate or strainer plate, and the screws and threaded inserts which together create the studs necessary for engagement of the grate or strainer plate. The taps, insertion tool, and spanner wrench can be included for convenience. The spanner wrench could have the form shown in FIG. 9, or it could be similar to tool 30 of FIG. 8, or it could have some other construction.

By creating threaded bores, and installing studs into these threaded bores, one can retrofit an installed drain body fitting so as to accommodate the grate of the present invention.

The invention may be modified in various ways. The invention is not limited to use in marine environments, but can be used to secure grates for drain fitting bodies, or valved drain fitting bodies, in other applications. The specific configuration of the holes in the grate can be changed to suit particular needs. The number and position of the elongated openings could be varied, as long as these openings define at least a generally circular arc so that the grate can be rotated between a locked and an unlocked position. While a preferred material for the components of the present invention is metal, it will be apparent that the materials used to make the drain fitting, the grate, the studs, and the other components, can be changed to suit the drain application. These and other modifications, which will be apparent to the reader skilled in the art, should be considered within the spirit and scope of the following claims. 

1. A self-locking grate for a drain fitting, comprising: a plate having a plurality of strainer holes, the plate further comprising a plurality of elongated openings which are distinct from the strainer holes, each elongated opening including a region of enlarged diameter relative to other regions of said elongated opening, the elongated openings defining at least a generally circular arc.
 2. The grate of claim 1, wherein at least one of said elongated openings has a ledge having a depth which varies along said opening.
 3. The grate of claim 1, wherein the plate has a generally circular shape, the plate having a periphery, and wherein the elongated openings are located in a vicinity of the periphery of the plate.
 4. The grate of claim 2, wherein the plate has a generally circular shape, the plate having a periphery, and wherein the elongated openings are located in a vicinity of the periphery of the plate.
 5. The grate of claim 1, further comprising a tool having means for supporting a pair of spaced-apart prongs, the prongs being sized to fit simultaneously within at least two of said strainer holes and said openings, wherein movement of the tool, when the prongs are inserted into said holes or openings, causes rotation of the grate.
 6. The grate of claim 5, wherein at least one prong of the tool is pivotable relative to another prong, wherein positions of the prongs can be adjusted so that the prongs fit simultaneously into holes and/or openings of the grate.
 7. In combination, a self-locking grate and a drain fitting body, the grate comprising a plate having a plurality of strainer holes, the plate further comprising a plurality of elongated openings which are distinct from the strainer holes, each elongated opening including a region of enlarged diameter relative to other regions of said elongated opening, the elongated openings defining at least a generally circular arc, and wherein the drain fitting body comprises means for supporting a plurality of studs, wherein the studs are positioned to coincide with positions of said regions of enlarged diameter of said elongated openings, and wherein the studs are sized to pass through said regions of enlarged diameter but not through other regions of said elongated openings, wherein the studs can engage the grate when the grate has been rotated.
 8. The combination of claim 7, wherein each stud has a head, wherein at least one of said elongated openings has an inclined ledge having a depth which varies along said opening, the inclined ledge comprising a cam surface for wedging the grate against an underside of the head of the stud.
 9. The combination of claim 7, wherein the plate has a generally circular shape, the plate having a periphery, and wherein the elongated openings are located in a vicinity of the periphery of the plate.
 10. The combination of claim 8, wherein the plate has a generally circular shape, the plate having a periphery, and wherein the elongated openings are located in a vicinity of the periphery of the plate.
 11. The combination of claim 7, further comprising a tool having means for supporting a pair of spaced-apart prongs, the prongs being sized to fit simultaneously within at least two of said strainer holes and said openings, wherein movement of the tool, when the prongs are inserted into said holes or openings, causes rotation of the grate relative to the drain fitting body.
 12. The combination of claim 11, wherein at least one prong of the tool is pivotable relative to another prong, wherein positions of the prongs can be adjusted so that the prongs fit simultaneously into holes and/or openings of the grate.
 13. A method of installing a grate on a drain fitting body, comprising: a) placing a grate onto a drain, wherein the drain includes a plurality of studs, and wherein the grate includes a plurality of elongated openings, each of the elongated openings having an enlarged diameter portion sized to accommodate said studs, the grate being placed such that the studs pass through the enlarged diameter portions of said openings, and b) rotating the grate so that the studs are no longer positioned within the enlarged diameter portions, wherein the grate becomes locked onto the drain fitting body.
 14. The method of claim 13, wherein the enlarged diameter portions are located at one end of the elongated openings, and wherein the elongated openings have an opposite end at which the opening has a diameter smaller than that of the enlarged diameter portion, and wherein step (b) includes rotating the grate until the studs are located in a vicinity of said opposite end of the elongated openings.
 15. The method of claim 13, further comprising turning the grate until the studs are positioned within the enlarged diameter portions, and lifting the grate from the drain.
 16. The method of claim 13, wherein the rotating step comprises applying force to a tool which is in engagement with the grate, the tool having means for supporting a pair of spaced-apart prongs, the prongs being sized to fit simultaneously within at least two holes or openings in the grate, wherein movement of the tool, when the prongs are inserted into said holes or openings, and torque is applied, causes rotation of the grate relative to the drain.
 17. The method of claim 16, wherein at least one prong of the tool is pivotable relative to another prong, and wherein the method includes the step of adjusting a position of said at least one prong so that the prongs fit simultaneously into holes and/or openings of the grate.
 18. A kit for modifying a drain fitting so as to accommodate a self-locking grate, the kit comprising: a) a plate having a plurality of strainer holes, the plate further comprising a plurality of elongated openings which are distinct from the strainer holes, each elongated opening including a region of enlarged diameter relative to other regions of said elongated opening, the elongated openings defining at least a generally circular arc, and b) means for providing studs in a drain fitting, the studs having heads which are sized to engage at least a portion of the elongated openings of the plate.
 19. The kit of claim 18, further comprising at least one tap for creating a threaded bore for receiving said studs in the drain fitting.
 20. The kit of claim 18, further comprising a tool having means for supporting a pair of spaced-apart prongs, the prongs being sized to fit simultaneously within at least two of said strainer holes and said openings, wherein movement of the tool, when the prongs are inserted into said holes or openings, applies a torque to the grate. 